Since the 1940's ophthalmic devices in the form of intraocular lens (IOL) implants have been utilized as replacements for diseased or damaged natural ocular lenses. In most cases, an IOL is implanted within an eye at the time of surgically removing the diseased or damaged natural lens, such as for example, in the case of cataracts. For decades, the preferred material for fabricating such IOL implants was poly(methyl methacrylate) (PMMA), which is a rigid, glassy polymer.
Softer, more flexible IOL implants have gained in popularity in more recent years due to their ability to be compressed, folded, rolled or otherwise deformed. Such softer IOL implants may be deformed prior to insertion thereof through an incision in the cornea of an eye. Following insertion of the IOL in an eye, the IOL returns to its original pre-deformed shape due to the memory characteristics of the soft material. Softer, more flexible IOL implants as just described may be implanted into an eye through an incision that is much smaller, i.e., less than 4.0 mm, than that necessary for more rigid IOLs, i.e., 5.5 to 7.0 mm. A larger incision is necessary for more rigid IOL implants because the lens must be inserted through an incision in the cornea slightly larger than the diameter of the inflexible IOL optic portion. Accordingly, more rigid IOL implants have become less popular in the market since larger incisions have been found to be associated with an increased incidence of postoperative complications, such as induced astigmatism.
With recent advances in small-incision cataract surgery, increased emphasis has been placed on developing soft, foldable materials suitable for use in the manufacture of IOL implants. In general, the materials of current commercial IOLs fall into one of three categories: silicone, hydrophilic acrylic and hydrophobic acrylic.
In general, IOLs, once implanted, have a tendency to allow lens epithelial cells (LECs) to attach and spread on the surface of the IOL. Such LEC growth on IOL surfaces causes undesirable IOL opacification requiring IOL explantation and replacement. Also undesirable, IOLs manufactured from silicone materials tend to absorb silicone oils used in subsequent unrelated ocular surgeries causing opacification of the IOL.
Because of the noted shortcomings of current biocompatible polymeric materials available for use in the manufacture of ophthalmic devices such as IOLs, there is a need for stable, biocompatible polymeric materials suitable for use in the manufacture of IOLs that reduce or eliminate LEC growth on surfaces thereof upon implantation-and reduce or eliminate the risk of IOL absorption of silicone oil in the case of subsequent ocular surgeries.